After comparing App platform with Heroku and render, I see no one wins.
App platform:
  1. my rails app was so slow in your platform (others platform was fast, even Codeanywhere server was fast)
  2. Builds are slow
  3. bandwidth is $0.10!! this is not D.O style.
  4. no cron job ( i know it's coming)
  5. no enough docs
  6. No autoscale (render has it)
I wish I can throw all my websites to App platform but it needs some works